1953 Corsair water pump issues.

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  • September 13, 2015 at 3:28 am #2516
    20mercman
    Participant

      Kevin picked up a "free" 53 Corsair Navigator 5hp at Tomahawk this last month. I like the idea of "free" motors. ( $90.00 spent so far in the lower unit, that is why they are free!) Well, it was rusted up pretty good in the lower unit, so we replaced the needle and roller bearings and the prop shaft seal along with sending the old pump out to be rebuilt. Kevin cleaned up the ignition system and rebuilt the fuel system, and we were waiting for the pump to arrive. After an e-mail, and tracking that indicated that it arrived at my house over a week ago, I found my bride stashed it in a drawer and didn’t bother to tell me. 🙄 We put the pump in last night and the lower unit back together, hoping to be able to start it up today. It started fine, and pumped water like a fire hose! Great! As I was adjusting the carburetor, I noticed that the pee stream was gradually getting less and less. By the time I had the thing running properly, it was starting to overheat. 😕 After I let it cool down, I restarted it, and ip pumped nothing out of the water indicator but steam when it starts to heat up. It gets hot quickly, so I can’t run it very long. We are going to pull the pump back out, means taking the lower unit front cover off again, and see if there is anything going on with the pump. I tell you, part of me really likes these Scott products, but these things have beaten me on these pumps and keeping them cool. Does anyone have any ideas as to why I am having this problem. This has the original coils, and that thing will throw a SPARK! :mrgreen: If I could just get it to cool, this would be a very nice little kicker. Needs paint and decals, but it is a nice match to our 7.5hp Corsair, which also runs HOT. 👿

      Steve

      September 13, 2015 at 5:28 am #23736
      frankr
      Participant

        US MEMBER PAY BY CHECK

        Does it have the stainless steel pump cartridge? Is it flat on the bottom? Corrosion build-up under the cartridge makes the bottom bulge upward, putting the squeeze on the impeller, quickly destroying the impeller.

        September 13, 2015 at 4:34 pm #23753
        billw
        Participant

          US Member

          Well, Frank’s probably right; but since panic is a no-fun emotion, I wouldn’t panic, YET… Sometimes when a motor sets for a long time, then the water starts flowing, corrosion and silt, etc, can plug things up, as it it starts to flush through. I’m personally hoping your impeller is okay….Those Scott ones usually are not cheap!!

          Long live American manufacturing!

          September 13, 2015 at 4:55 pm #23757
          jim-moffatt
          Participant

            US Member

            My guess from experience is that a vane from the old impeller blocked the water passages. The 1953 motors have the impeller under water and they usually work fine.

            September 13, 2015 at 8:58 pm #23781
            20mercman
            Participant

              Thanks for all of the suggestions. Here is a little more back story. I was able to retrieve all of the old parts of the impeller, so I don’t think that there is anything from the other pump in the motor. It does have the stainless pump cartridge, but we removed it when we serviced the lower unit, so there was nothing under the cup. We went to a meet this morning, and I have not had a chance to pull it apart to check the new pump. I will report back when we get it out and see what it looks like. After that, I am going to pull the exhaust baffle to see what’s inside there.

              Steve

              September 14, 2015 at 4:11 am #23819
              20mercman
              Participant

                Well, an update: Kevin pulled it apart tonight, pump was intact and in good condition, blew air through the cooling system. Put it all back together, started it up, same as the first time. Pumps beautifully, then starts to loose the steady stream. Then it starts to steam. We are now suspecting a head gasket or exhaust baffle gasket leak. Need to find gaskets for a 53 5hp Corsair if anyone has them.

                Steve

                October 25, 2015 at 3:30 am #26026
                20mercman
                Participant

                  Well, I finally had a chance to work on the Corsair today. I made a new exhaust baffle gasket, and pulled the head and cleaned up the surfaces. The bottom water passage under the cylinder head was completely blocked with corrosion and stuff. I was able to clean it out, and dressed up the gasket surfaces and put it back together. She runs great! I can lay my hand on the block while it has run for some time. I was hoping to be able to take it out tomorrow, but I have to leave town in the morning. I am sure this will run well on the boat, it really is a nice running little motor. This was in the "free" pile at Tomahawk, and we just felt sorry for it. After $40 in the water pump and shipping, (A real nice pump as it turned out, Thanks!) and about $50 in bearings and seals for the lower unit, (nothing is ever really free!) we have a really nice running motor. I will need to find decals and the correct shade of blue for the cowls, but it should be restored.

                  Steve

                  October 25, 2015 at 10:45 am #26031
                  billw
                  Participant

                    US Member

                    Nice story. For me, that’s what this hobby is about: Resurrection from the dead, where most other people wouldn’t have cared. I think that mechanical engineering and art have a lot in common. To me, every old machine is a kind of masterpiece that deserves respect. I think you did good!

                    Long live American manufacturing!

                    October 25, 2015 at 4:35 pm #26042
                    jeff-register
                    Participant

                      US Member - 2 Years

                      Steve,
                      I know for sure the Scott Guy Don after his passing by family has had all of his stock sold to another person, remains to be announced yet. Doug Penn has been rumered to have bought it all but still to be known at this time. I too own a few Scotts as my first motor over 35 years ago was a 1953 Firestone 7.5hp engine. Looking thru my Corsair parts book it shows O-rings below the impeller housing. The first goes above the pinion bearing to seal the drive shaft from above & the second is above that. The second fits the outside diameter of the stainless housing directly below the impeller housing above the other O-ring. Next the housing is sealed into the aluminum case with some kind of sealer. I used silicone caulk. Also both ends of the water tube has O-rings on them too. You should see the indent in the cav plate where it is to be placed. The shift rod also has an O-ring inside the small aluminum pipe that guides the rod into the gear cavity, but not much of a seal. I added a piece of blood pressure tubing to also seal the rod & the top of the case to help. Before Don passed he told me to check the three threaded holes for the cover to check for flatness & file until flush as they pull up & keep the case from sealing. The gearcase it’self I had machined deeper so I can now stack two pinion bearing seals for better driveshaftsealing, one up to keep oil in & the other to keep water out. The shafts are very hard to find without pits either. I used jb weld to fill them in, not perfect but smoothed out the sharp edges.

                      October 26, 2015 at 3:12 am #26075
                      20mercman
                      Participant

                        Thanks Jeff for the tips, and to Bill for the kind words. So far, the lower unit seems to be staying dry. I can see about the bolt holes keeping the case from making a tight seal. I will keep an eye on it to make sure that no water gets in it, or stays in it. As for this being what the hobby is all about, I couldn’t agree more. I am the classic sucker for the basket case. It seems that the worse they are, the more I want to restore them. I have a great deal of respect for the folks that want super clean original motors. Who wouldn’t want them? For me, I see some neglected or abused motor and want to get back among the living. A good portion of our collection were hulks or parts motors when we found them. These old Scott products have their good points. This thing shifts so nicely, very handy to fish with, good smooth idle. A lot to like. The only thing that I have some issue with is the choke set-up where you have to push the knob in while pulling the motor over. It would be nice to have a knob that would stay in choke mode, as the motor likes to pull up when you pull it.

                        Steve

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